Spark plug



Aug. 23, 1949. G. L. LANG 2,479,577

SPARK PLUG Filed May 17, 19415 fig-,2

mmv ma AT 1013MB Y Patented Aug. 23, 1949 UNITED STATES PATENT OFFICE SPARK PLUG I Gregor L. Lang, Longmeadow, Mass.

Application May 17, 1945, Serial No. 594,227

20 Claims. .(Cl.123---169) such a construction wherein the rate of increase in length of the electrode will be consistent with and relative to the rate of erosion or burning away of the electrode.

Another object is to provide a sparkplug having self-adjusting means for automatically retaining the relative positions of the electrodes and thereby eliminating or decreasing the necessity of adjustment or re-gapping of the electrodes.

Another object is to provide a sparkplug construction which will increase the number of engine hours obtainable between sparkplug overhaul periods.

Another object is to provide a sparkplug employing base metals or alloys thereof for. the

' firing electrodes which sparkplug will have at least the usable period between adjustments of a sparkplug having an electrode of a more precious metal.

Referring to the drawings:

Fig.1 is a side view, partially in section, of a sparkplug constructed according to the invention; and Fig. 2 is a'sectional view taken on line 2-2 of Fig. 1 looking in the direction of the arrows.

In the past difficulty has been encountered with internal combustion engines and particularly engines of the so-called high duty type such as aircraft engines, because of the erosion or burning away of the electrodes of the sparkplug, there'- by increasing the distance between the electrodes and interfering with the operation of the sparkplug and necessitating the re-gapping or adjustment of the electrodes at relatively frequent periods to avoid this difilculty.

While this difficulty has been overcome to some extent by the use of relatively precious metals such as tungsten and platinum instead of base metals such as nickel or a nickel steel alloy, the cost of manufacture of the sparkplug has thereby been increased and the sparkplug even when constructed with the precious metal electrodes still erodes or burns away although not as rapidly as when the electrodes are constructed of base metals.

It,therefore, is the principal object of this invention to provide a new and improved sparkplug construction which will eliminate the necessity of constructing all of the electrodes thereof of precious metal and which will allow an electrode to automatically compensate for the erosion or burning away of the electrodes, thereby increasing the number of engine hours obtainable between sparkplug overhaul or adjustment periods.

Referring more particularly to the drawing, wherein similar reference characters designate corresponding parts throughout the two views, the sparkplug shown embodying the invention comprises the metal shell I containing the ceramic or insulating member 2 having a longitudinal central bore or recess 3.

The shell i has the usual threaded portion 4 for securing the sparkplug in the opening in the head of an internal combustion engine in the usual manner, and this shell I is also provided with the usual electrodes 5 and 6 secured thereto in the usual manner. These electrodes 5 and 6 may be formed of precious metal such as tungsten or platinum or may be formed of a base metal such as nickel or a nickel steel alloy.

Within the central bore 3 in the plug insulator member 2 of ceramic or other suitable insulator material is the center electrode 1 which extends therethrough and has the usual portion 8 adjacent its upper end for connection to the ignition system of the engine. The center electrode is provided with a bored recess 9 which is preferably adjacent its end nearest the electrodes 5 otherwise caused to firmly grip or engag the electrode extension Ill to retain the parts in assembled relation.

Before the electrode extension It is positioned within the bore of the electrode, a quantity l2 of a suitable material is placed therein. This maon the fact that materials such as copper when converted to the oxide under the influence of heat, expand or occupy a greater space than was occupied by the copper before the forming of theoxide. Other materials oxidize to greater or lesser degrees and the rate of oxidation may be controlled by the selection of proper material and proper choice in size of the bore and/ or the size and shape of the discs or particles.

The material can, for example, consist of discs of metal such as copper, or as alternate discs of copper and 'steel, or copper and a free oxidizing material selected to produce free oxygen under the influence of heat or copper and a material selected to produce free sulphur under the influence of heat, and could have their adjacent surfaces serrated in order to prevent them from sealing or joining together against one another. Or this material could consist of copper grains or a mixture of copper grains and steel grains, or grains of other desired materials and metals, so long as the materials are selected and proportioned to produce a definite or desired rate of oxide growth or formation at a given temperature.

By having the material such as will form oxide or sulphate when heated by heat from the engine, the amount of .the growth or formation of the oxide will depend "upon the extent and amount of use of the engine and therefore with a proper selection of oxide-forming materials the growth of the electrode Hi can be controlled according to the use made of the engine with which the sparkplug is employed. By proper selection of materials the rate and extent of growth can be controlled.

If desired, means may be provided for permitting the hot fuel gases or engine combustion gases to enter the oxide expansion chamber, should this be deemed desirable or necessary in order to obtain the desired rate of growth.

From the foregoing it will be seen that I have provided simple, eflicient and economical means for obtaining all of the objects and advantages of the invention.

Having described my invention, I claim:

1. An electrode for a spark plug or the like, said electrode comprising two members mounted for relative movement and thermo-chemical actuated means for causing relative movement of r said members.

2. An electrode for a spark plug or the like, said electrode comprising two members, one of said members being mounted for movement away from the other of said members and thermochemically operated-means between said members and adapted to cause movement of said movable member away from the other of said members, said means being electrically conducting for conducting current from one to the other of said members.-

. 3. An electrode for a spark plug or the lilze, said electrode comprising two members with one of said members being mounted ,for relative movementin a direction away from the other of said members, and a plurality of pieces of ther-- mo-chemically actuated material between said members and adapted to cause movement of said movable member away from the other of said members.

4. An electrode for a spark plug or the like, said electrode comprising two members with one of said members being mounted for relative movement in a direction away from the other of said members. and a plurality of pieces of thermo-chemically actuated material between said members and adapted to cause movement of said movable member away from the other of said members, said thermo-chemically actuated material belng electrically conducting for conducting current from one to the other of said members.

5. In a device of the character described, a shell, an insulating member within said shell, electrode means on said shell,. and electrode means within said insulating member, one of said electrode means having a portion mounted for movement, and non-retractable thermally actuated expanding mean engaging said movably mounted portion of said electrode means for automatically permanently adjusting the position of said portion relatively to the other electrode to thereby compensate for any erosion of the electrodes.

6. In a device of the character described, an electrode, means for supporting a second electrode in operable position relatively to said first electrode, and thermally actuated chemical means engaging one of said electrodes for causing movement of said electrode and thereby automatically adjusting the relative positions of said electrodes to thereby compensate for any change in the relative positions of said electrodes.

7. A spark plug having spaced electrodes and non-retractable thermally actuated expanding means intermediate the ends of one of said electrodes for automatically.permanently adjusting a portion of said electrode to thereby adjust the relative positions of said electrodes to thereby compensate for any change in the relative positions of said electrodes.

8. A spark plug having spaced electrodes and thermally actuated mean intermediate the ends of one of said electrodes for automatic non-retracting adjustment of said electrodes during the use of the spark plug to thereby compensate for any change in the relative position of said electrodes.

9. A spark plug including an insulating shell having a bore and an electrode in said bore, said electrode comprising two portions, one of said portions having a bore adapted to receive the other portion which is adjustably retained in said bore, and means between the adjacent ends of said electrodes for forming a growth between said portions for causing automatic non-retracting movement of one of said portions relative to the other of said portions.

10. -A spark plug including an insulating shell having a bore and an electrode in said bore, said electrode comprising two portions, one of said portions having a bore adapted to receive a portion of the other portion which is adjustably retained in said bore, and means expanded by chemical change between the adjacent portions of said electrodes for forming a growth between said portions when the electrode is heated for causing automatic non-retracting movement of one of said portions relative to the other of said portions.

11. A spark plug including an insulating shell having a bore and an electrode in said bore, said electrode comprising two portions, one of which is adjustable relative to the other, and oxidefcrming means between the adjacent ends of said portions for causing automatic movement of one of said portions relative to the other of said portions.

12. A spark plug comprising a metallic outer shell having means for securing the spark plug in position on an engine, an insulating member within said shell and having a longitudinal bore; an electrode within the bore in said insulating member,.said electrode comprising two conducting members with one of said members extendin into a bore in the other of said members, and thermo-chemically actuated means in said last named bore between the adjacent portions of said electrodes and adapted to react to heat from the engine on which the spark plug is employed for causing automatic movement or growth of one of said electrodes relative to the other electrode and thereby compensate for any eroding or burning away of the electrode.

13. A spark plug comprising a metallic outer shell having means for securing the spark plug in position on an engine, an insulating member within said shell and having a longitudinal bore. an electrode within the bore in said insulating member, said electrode comprising two conducting members with one of said members extending into a bore in the other of said members, and means in said last named bore between the adjacent portions of said electrodes for causing automatic oxide growth and adjustment of one of said electrodes and thereby compensate for any eroding or burning away of the electrode.

14. A spark plug comprising a metallic outer shell having means for securing the spark plug in position on an engine, an insulating member within said shell and'having a longitudinal bore, an electrode within the bore in said insulating member, said electrode comprising two conducting members with one oi said members extending into a bore in the other of said members, and granular oxide-forming means in said last named bore between the adjacent portions of said members for causing automatic oxide growth oi said electrode and thereby compensate for any eroding or burning away of the electrode.

15. A spark plug including an insulating shell having a bore and an electrode in said bore. said electrode comprising two spaced portions and chemical means between said portions for causing automatic non-retracting movement of one of said portions relative to the other or said portions.

16. In a spark plug, a two part electrode and means between said electrode parts for effecting change in position of one of said parts through chemical change of said means.

17. In a spark plug, a two part electrode, one of said electrode parts being mounted for movement relative to the other of said parts, and means intermediate said parts for effecting a change in the relative positions of said parts through chemical change of said means.

18. An electrode for a spark plug or the like for an internal combustion engine, said electrode comprising two portions mounted for relative movement and means actuated by running of the engine for causing non-retractable relative movement of said portions, said means being thermally actuated.

19. In a device of the character described, a member having two portions, one of said portions being mounted for movement relative to the other portion and means for causing non-retractable movement of said movably mounted portion, said means being thermo-chemically actuated.

20. In a device of the character described, a pair of members, one of said members being mounted for movement relative to the other member and means for causing non-retractable movement of said movably mounted member, said means being thermo-chemically actuated.

GREGOR L. LANG.

REFERENCES CITED The following references are of record in the die of this patent:

UNITED STnTES PATENTS Number Name Date 1,363,842 Crowther Dec. 28, 1920 1,405,701 white Feb. 7, 1922 1,501,368 Powell July 15, 1924 1,597,963 Gantner Aug. 31, 1926 2,110,652 Nowosielski Mar. 8, 1938 

